Process for removing an impurity from a chlorosilane mixture

Abstract

A process for removing an impurity from a mixture containing at least one chlorosilane and/or organochlorosilane and at least one impurity from the group comprising a boron compound, a phosphorus compound, and an arsenic compound is provided. The process includes contacting the liquid mixture with an unfunctionalized organic polymer having pores with an average pore diameter of less than 50 Å, the average pore diameter being determined in accordance with DIN ISO 66134, and optionally removing the unfunctionalized organic polymer.

The invention claimed is: 
     
       1. A process for removing an impurity from a mixture containing at least one chlorosilane and/or organochlorosilane and at least one impurity from the group comprising boron compound, phosphorus compound, and arsenic compound, said process comprising the steps of:
 a) contacting the liquid mixture with an unfunctionalized organic polymer having pores with an average pore diameter of less than 50 Å, the average pore diameter being determined in accordance with DIN ISO 66134; 
 b) optionally removing the unfunctionalized organic polymer. 
 
     
     
       2. The process as claimed in  claim 1 , wherein the average pore diameter is 15 to 48 Å. 
     
     
       3. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer has a pore count maximum at a pore diameter of <100 Å. 
     
     
       4. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer has a specific surface area of 25 to 1050 m 2 /g. 
     
     
       5. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer has a specific surface area of >1050 m 2 /g, with the proviso that a value of 2500 m 2 /g is not exceeded. 
     
     
       6. The process as claimed in  claim 1 , wherein the chlorosilane is an acyclic chlorosilane of the general formula H x Si n Cl (2n+2−x) , where 0≤x≥12 and 1≤n≥5, and/or a cyclic chlorosilane of the general formula H x Si n Cl (2n−x) , where 0≤x≥20 and 5≤n≥10. 
     
     
       7. The process as claimed in  claim 1 , wherein the chlorosilane is selected from the group comprising silicon tetrachloride, trichlorosilane, dichlorosilane, monochlorosilane, and combinations thereof. 
     
     
       8. The process as claimed in  claim 1 , wherein the organochlorosilane is an acyclic organochlorosilane of the general formula H x Si n R 3   y Cl (2n+2−x−y) , where 0≤x≥11, 1≤n≥5, and 1≤y≥12, and/or a cyclic organochlorosilane of the general formula H x Si n R 3   y Cl (2n−x−y) , where 0≤x≥19, 5≤n≥10, and 1≤y≥20 and where R 3 =alkyl, aryl, alkylaryl or alkoxy. 
     
     
       9. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer contains a proportion of water of less than 5% by weight. 
     
     
       10. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer is selected from the group comprising polyethylene, polystyrene, polydivinylbenzene, styrene-divinylbenzene copolymer, and combinations thereof. 
     
     
       11. The process as claimed in  claim 10 , wherein the unfunctionalized organic polymer comprises a styrene-divinylbenzene copolymer. 
     
     
       12. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer comprises a hypercrosslinked polymer. 
     
     
       13. The process as claimed in  claim 1 , wherein the unfunctionalized organic polymer in particulate form has an average particle size of 0.149 to 4.760 mm. 
     
     
       14. The process as claimed in  claim 1 , wherein in step a) the unfunctionalized organic polymer is in the form of a fixed bed in one or more containers arranged in series or in parallel, through which the mixture passes in a continuous stream. 
     
     
       15. The process as claimed in  claim 14 , wherein the hydrodynamic residence time of the mixture in the reaction volume is 0.1 to 100 000 s.